LED Protrusion Pattern Structure for Better Light Extraction
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Solution Overview
Problem
Light emitting diodes suffer from reduced light emission efficiency due to light being trapped inside the device, necessitating improvements in light extraction and epitaxial process efficiency.
Innovation Solution
A light emitting device with a substrate featuring a first protrusion pattern and a second protrusion pattern of varying height, pitch, and material refractive index, along with a buffer layer, to enhance light extraction efficiency and epitaxial process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single protrusion pattern is formed on the substrate, then the structure is simple and manufacturing is easier, but light extraction efficiency is insufficient due to light being trapped inside the device
Solution Approach 1:
The invention divides the protrusion pattern into two distinct segments: a first protrusion pattern formed directly on the substrate and a second protrusion pattern formed on the base layer. This segmentation allows each pattern to serve different functions in light extraction, with the first pattern providing initial scattering and the second pattern providing additional extraction pathways, thereby resolving the contradiction between structural simplicity and light extraction efficiency.
Solution Approach 2:
The invention adds a vertical dimension to the protrusion pattern structure by forming the second protrusion pattern on top of the base layer rather than directly on the substrate. This dimensional change creates multiple interfaces and scattering planes at different heights, enabling more effective light extraction while maintaining manufacturing feasibility through sequential formation processes.
2Loss of energy
If the second protrusion pattern has lower height and smaller pitch, then light extraction efficiency improves through diversified reflection patterns, but manufacturing precision requirements increase
Solution Approach 1:
The invention optimizes the geometric parameters of the second protrusion pattern by setting its height to be lower and its pitch to be smaller than the first protrusion pattern. These parameter changes create more numerous and closely spaced scattering centers that diversify light reflection patterns, improving extraction efficiency. The lower height and smaller pitch are achieved through controlled epitaxial growth processes that can precisely regulate layer thickness and pattern dimensions.
3Loss of energy
If multiple protrusion patterns with different materials are used, then light extraction efficiency improves through refractive index manipulation, but device complexity increases
Solution Approach 1:
The invention employs composite material structures where the first protrusion pattern, base layer, and second protrusion pattern are composed of different materials with distinct refractive indices. This composite structure creates multiple refractive index interfaces that enhance light scattering and extraction. The materials are selected to provide optimal optical contrast while maintaining lattice matching for defect-free epitaxial growth, balancing optical performance with structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves improved light extraction efficiency through diversified light reflection patterns and refractive index manipulation, enhancing overall light emission performance.
Implementation Method 1
configuring materials of the protrusion patterns in consideration of a relationship between refractive indices
Implementation Method 2
improve light extraction efficiency through diversifying a pattern of light reflected by the first protrusion pattern
Data Source
Figure 1
Figure 2(a)~2(e)
Figure 3(a)~3(b)
AI summary
This document is about a light emitting device having a protrusion pattern structure. A light emitting device to be proposed includes: a substrate including a first protrusion pattern on its top surface; a base layer formed on a top of the substrate; a first electrode layer formed on a top of the base layer; a light emitting layer formed on a top of the first electrode layer; and a second electrode layer formed on a top of the light emitting layer, wherein the base layer includes a second protrusion pattern different from the first protrusion pattern on a top surface thereof.